FUMIGATION
The most effective method of control is tent fumigation. There is only one fumigant used for the control of drywood termites in Hawaii and it is VIKANE, sulfuryl fluoride. It was developed in the 1950’s and has been widely used since then. It is a transported as a liquid in pressurized cylinders but vaporizes at 67 degrees Fahrenheit and it is toxic especially to insects. It will control a broad range of insects but it is generally used to control drywood termites as there are usually more inexpensive ways of treating roaches and other pests. Different insects will be killed with different doses of VIKANE so an insect with a high metabolism, such as a fly, will succumb much quicker than termites. Spiders, with very low metabolic rates, will require twice as much fumigant as termites. Another variable is not just the quantity on the fumigant introduced to the structure but the length of time it is kept there. Therefore, a structure can be fumigated for a shorter period of time if the quantity of the fumigant is increased. The dosage also depends on a number of factors such as the type of soil under the building, the wind speed, the ambient temperature and how well contained the gas is. Fumigation of houses is a real blend of science and art. Its objective is to confine a sufficient amount of gas for a long enough time to allow it to penetrate all the areas of the house and kill all the termites. VIKANE is effective not just because it is toxic but because it is able to penetrate deep into the wood through the pores. These pores are so small they can only be seen with an electron microscope. Being able to penetrate into openings this small it can easily penetrate the relatively large termite galleries. This penetration is called sorption. Another desirable quality of VIKANE is it’s rate of desorption. It does not bind with the wood and everything else in the house and leave a residue. The gas diffuses from areas of higher concentrations to areas of lower concentrations so while the tent covers the house and contains the gas it moves to areas where there is little or no gas. Once the tent is removed the diffusion continues to the outside where there is no gas until all the gas has escaped. The gas is heavier than air so circulating fans are used inside the house to insure that areas such as the attic and rafters are covered. Once released into the atmosphere it is broken down through hydrolysis.

REPLACEMENT OF INFESTED MATERIALS
Replacement of the infested material works but only when you can be sure all the areas if infestation have been identified. This may be appropriate in a condominium when the front door has been heavily infested and damaged and the likelihood of spot treatment being effective is not good.

SPOT TREATMENT
Spot treatment can sometimes be effective when there is a limited infestation and it is accessible. An insecticide is injected into the termite galleries. If it reaches the termites they are instantly killed. The problem is getting it to the termites. The biggest failure results when the infestation is large and the insecticide doesn’t penetrate adequately or when there are infestations that are not visible. Treating plywood is difficult as the liquid does not penetrate the various layers especially with thicker pieces.

A variation on this is the application of Tim-bor to the surfaces of the wood. Tim-bor is a combination of sodium oxide and boric oxide applied with water. It is used to pressure treat lumber at a facility at Campbell Industrial Park but can also be used by a licensed pest control operator with a license to use restricted use pesticides. According to the manufacturer, applying it to the surfaces of wood will kill termites inside the wood. The limitations are that it can not be used where it will be washed away with rain, it should be applied to an unpainted surface and some infestations may be inaccessible such as those inside wall.